This invention relates to a circuit breaker mechanism. In particular, the invention relates to the arrangement of a contact carrier forming part of the mechanism.
The conduction path of a circuit breaker typically includes a line terminal and a load terminal, with a set of contacts and a load sensing device between the contacts. Conventionally, the set of contacts comprises a fixed contact and a moving contact, with the moving contact being mounted on a contact carrier which is supported pivotably on a frame member of the mechanism. In known miniature circuit breakers, the contact carrier is mounted pivotably to an operating handle which in turn is supported pivotably on a handle frame of the circuit breaker mechanism. The handle frame also serves as part of the conduction path of the mechanism. A flexible conductor, known as a pig-tail, is welded to the moving contact carrier and to the handle frame and flexes with the movement of the contact carrier between a first position in which the contacts are closed and a second position in which the contacts are open.
The flexible pig-tail is typically welded to the contact carrier and the handle frame. The welding process can cause distortion of the contact carrier, resulting in the contact carrier rubbing on the shell or housing of the circuit breaker, negatively affecting the switching action of the mechanism. It will also be appreciated that the stiffness, the orientation and the length of the flexible pig-tail have a direct effect on the contact pressure and other operating characteristics of the circuit breaker mechanism.
It is an object of invention to provide a circuit breaker mechanism which reduces or does away with the need for a flexible conductor or pig-tail of the kind described above.